UPDATE: See the bottom of this question for what I did to solve the problem.I'm trying to understand how the ItemsSource and DataContext properties work in a Silverlight Toolkit DataGrid. I'm currently working with dummy data and trying to get the data in the DataGrid to update when the value of a combo box changes.
View 2 Replies
I'm trying to create a datagrid with auto generating columns. Let's say my Collection is a property named Articles of my viewmodel of type ObservableCollection<ArticleWrapper>.
I bind now the ItemsSource to this collection:
<wpf:DataGrid ItemsSource={Binding Articles} />
The class ArticleWrapper is like this:
[c#]
public class ArticleWrapper
{
public ArticleConfigurationSet ArticleConfigurationSet { get; set; }
public string Description { get; set; }
[Code]....
But now my problem: I want to bind the displayed data to my ArticleConfigurationSet property. But I cannot change my ItemsSource Binding, because the SelectedItem property of the datagrid must be of ArticleWrapper (for command handling).
The datagrid should also look like this:
I'm going through an XML file of articles and the journalist(s) that wrote them. As we are adding the articles into _Data our datacontext we may come across a journalist that needs adding so we do this: [code] However subsequently we may come across this same journalist again and nothing is returned when we do this: [code] So it uses the code above again to insert the same journalist again.Once all of our inserts are done we do a submitchanges. At this point it has a head fit:INSERT statement conflicted with COLUMN FOREIGN KEY constraint 'FK_ articles_ journalists_journalists'. The conflict occurred in database 'blah', table 'journalists', column 'id'. The statement has been terminated.From looking through the sql generated in sql profiler you can see that it is trying to add some journalists more than once, this will fail as the name must be distinct. The subsequent records that are trying to be inserted with these journalists are failing as the journalist wasn't updated.Surely if I have a collection of journalists, add some to it and then look in my collection I should see all of them and not just the original ones.
View 3 RepliesI am trying to set the itemssource for my WPF-based VB 2010 project to a datatable item. The datatable is "roster_table" and the column name I want to display the items from in the list box is "DATA_NAME". The listbox is "lstNames".
I can't find a straight answer anywhere. How do I set the itemssource for the listbox to the datatable's column, as described above?
I have a context menu on my DataTemplete for a list box, and that menu will contain links to Favourite and Retweet the tweet (the menu item) But I don't know how to get the information about the Tweet in code. I am trying the following Line:
[Code]...
I have some data in my Linq.DataContext.I had succes in converting it to an XSD - Schema, using the following code:
Dim changeset As System.Data.Linq.ChangeSet = c.GetChangeSet()
Dim objDic As New Dictionary(Of System.Type, List(Of Object))
If Not changeset Is Nothing AndAlso Not changeset.Inserts Is Nothing AndAlso Not
[code].....
I am setting my viewmodel as datacontext in my xaml but I override it to my view to make few functions work however to achieve the visibility on some grids and I have a property in my VM can I override my datacontext back to my VM? If so how? I have a stackpanel that has datacontext overriden as my grid and within that stackpanel I need to change the datacontext for a button.
View 1 RepliesI'm trying to get images to display in a WPF ListView styled like a WrapPanel as described in this old ATC Avalon Team article: How to Create a Custom View. When I try to populate the ListView with a LINQ-to-Entities queried collection of ADO.NET Entity Framework objects I get the following exception:
[Code]...
I would like to know if its possible to discard changes of only one record of only one table in datacontext. I use databind to bind my controls on a form. I modify one record at a time. after the modification, the user have to hit save button to validate. But he can hit cancel. I would like that the cancel button discard all the changes that the user has done. Is it possible?
View 3 RepliesI asked a question earlier where I was told a simple way to "bind data to objects" is to just run a SqlConnection(connectionString). The response also included a comment saying I could get fancy with L2S and Entity Frameworks, so I looked deeper into those. It seems all you have to do with the DataContext object is point to the database. Why would SqlConnection be a benefit? What is the difference (or pros/cons) of using either one of these? Is one more "standard"? Is one more modern?
View 1 RepliesHow to bind a textbox in design view to a LINQ to SQL datacontext class?
View 3 RepliesI have an object that may have been inflated via a plain old DataContext, or may just have been new-ed up with just its .ID property set. There's no way to know for sure. I'm looking to rehydrate the entire object from whatever is in the database. If the object was new-ed up, I can call .Attach() on the table object and refresh from the Data Context with no trouble. But, if the object was already inflated from the DataContext I get the error: "Cannot attach an entity that already exists.". There's no timestamp field or anything like that - just an integer primary key being used to control the rehydration. I'd like to know if there's a way to conditionally attach. Here's the code - it works the way I want it to, but this seems a hackish way to go about it:
' myDC is a shared instance of a vanilla DataContext...
' myObj is an instance of a linqed-up `SomeLinqObject`
Dim tbl = myDC.GetTable(Of SomeLinqObject)()
[Code[,,,,,
I'm trying to find a way to have the DataContext available from within Entities.
I want to do something like this:
partial public class MyEntity
public DataContext as MyDataContext
private sub OnLoaded()
[Code]....
This should be pretty easy, but it throws VS2008 for a serious loop.I'm trying out WPF with MVVM, and am a total newbie at it although I've been developing for about 15 years, and have a comp. sci. degree. At the current client, I am required to use VB.Net. I have renamed my own variables and removed some distractions in the code below, so please forgive me if it's not 100% syntactically perfect! You probably don't really need the code to understand the question, but I'm including it in cas.
I have a very simple MainView.xaml file:
<Window x:Class="MyApp.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
[code].....
I am preparing to deploy a web service that uses SqlConnection primarily as its means to get to the database, and I am adding some new methods that use a DataContext instead of thatand the default constructor and DBML file would use a connection string refering to my development machine (I believe...)
View 1 RepliesI am new to WPF and the MVVM design pattern this month, and more than a little out of practice in general. To learn, I've been playing around with textboxes, rectangles, and ways to display them in a window. I began with Ashley Davis' excellent "Simple Drag Selection in WPF" tutorial, which walks through creating a view model for a collection of rectangles, binding a listbox to said collection, and styling the listbox with a canvas, creating a data template for the rectangles, as well as basic "rubber band" selection logic.
I have since built on this tutorial to improve the drag selection so that it behaves much more like selection does in windows explorer, and to allow resizing the rectangles from the corners or edges.All was well until I changed the MainWindow.xaml in an effort to include a column on the side for various buttons and controls, thus moving the "editor surface" grid from inside a 1x1 grid on the main window to a column of a 1x2 grid, moving the data template to the grid's resources (since it will be the only element in the window that needs it). As soon as I did this, subroutines that I wrote which interact with the listbox started misbehaving--rubber band selection no longer works. There's no visual indication that listbox items are being selected (they were highlighted previously), and interrogating listBox.SelectedItems.Count after a drag-selection mouseUp event returns a zero.
After some experimentation, reading many questions on this site and sections of my WPF Unleashed book, and going over the msdn databinding overview, as of this morning I still cannot find my mistake(s). I believe it is a data binding mistake or incorrect data context.Some details about the view models involved:
DataFieldViewModel
...implements INotifyPropertyChanged and exposes properties for its (in this case a rectangle and a textbox) X,Y position, width, height, visibility, and selection status (a way to track it across several rubber band selection operations)
PageViewModel
...implements INotifyPropertyChanged, and has among other things an ObservableCollection of type DataFieldViewModel, called DataFields, and exposes it as a ReadOnly Property.Here's a look at MainWindow.xaml.vb and one of the broken subs:
Namespace EditorUI
'
' The main window of the editor.
[code]....
I am writing an application that has to read and interpret data stored in some PDF files. The reading part is done but I am only able to get a dump of all the words on a page and not the format of the words. What I mean is that if I have to extract a table, I am getting the numbers in the table but not the markup which defines the table.
Further, there is some formatting used which displays a few of these numbers within parentheses (meaning that those numbers are negative) but the parentheses themselves are not part of the text. Hence, I am not able to distinguish between positive and negative numbers present in the PDF table!
How do you get the PDF markup along with the text? Is a PDF similar in structure to an XML with tags used to markup tables etc.? If not, then, is there a resource which describes the salient features of the PDF DOM? I am using VBA and the Acrobat library (AcroExch etc.)
I have a LINQ to SQL DataContext with all my tables and all my stored procedures in it. Let me first start off by saying that we are upgrading our project from an access project to a WPF project. So in the Access project you could set a forms datasource to a stored procedure and edit and add new information. So in my WPF project on the page load I call my stored procedure to return an ISingleResult and then call a function to set the binding on every single textbox on the form. One is there an easier way to do this and two what if I want to add a new record since the textbox's are binded to an ISingleResult?
View 2 RepliesI am trying to use my first predicate and I generate the error:Method 'Public Function FindIndex(list As MyProgram.HTMLFiles) As Boolean' does not have the same signature as delegate 'Delegate Function Predicate(Of T)(obj As String) As Boolean'.[code]
View 12 RepliesI have this RichTextbox in my vb.net form and I would like to when a user click a button, for example to embold the selected text, how would I do this.Also, I do NOT want to use the standard vb.net expressions such as RichTextBox1.SelectedText.Font.Bold = true. I want to do something like RichTextbox1.SelectedRTF="[bold]" & RichTextBox1.SelectedRTF & "[/bold]" or whatever RTF looks like.Can I just add the RTF options random places or can a RichTextBox return an error if the text is in wrong format. I'm mostly looking for info on how to work with RTF without using the standard vb expressions.
View 1 RepliesMy goal is to read a data streaming from a machine the streaming is divided in tre main parts,the first is a 10 byte array that declare the length of the second and third part.The second one, the header, is a 22 DWORD (*32bit) ( 88 byte ) structured of mixed data types.I can easly read the value inside this header when the DWORD contains just one information using something like: [code] My problem starts because some of these DWORD contains several indipendent informations, for example DWORD #4 [ channel 2 peaks 31..16] [channel 1 peaks 15..0].For what I understood the first 16 bits ( so 2 bytes) are used to store the information of the first channel , while the second 16 bits are used for the second channel, I tryed converting the first 2 byte with System.BitConverter.ToUInt16()but without success.Can someone explain me what to do and how these numbers are supposed to be stored?
View 6 Repliesso i have a class called FOOTBALL,then another 3 classes/forms that inherit FOOTBALL, they control score (SCOREBOX), possession (POSSBOX), and quarter (QUARTERBOX).the FOOTBALL class has 4 variables, "score" (array of 2 ints), "teams" (array of 2 strings), "possession" (boolean), and "quarter" (int)after that i have another form called MAINBOX, which creates new instances of the 3 classes (SCOREBOX, POSSBOX, and QUARTERBOX) (like this: private scoring = new SCOREBOX)... however they all technically create their own FOOTBALL classes, so I cannot connect them.
View 4 RepliesI started out with VB.NET but now mostly do C#. I never really got to grips with events in VB. I'm trying to translate an old VB.NET program (from 2002) into C#. I've dealt with everything apart from statements such as these:
Public Event UpgradeProgress(ByVal strProgressString As String, _
ByVal strCurrentFile As String, ByVal intProgressPercent As Integer, _
ByVal lngTimeRemaining As Long, ByRef blnCancel As Boolean)
[code]....
It is my understanding that in .Net 4.0, VB will have an in-memory compiler.
I have to admit I don't know a lot about the compilers so I'm trying to understand the advantage of this as compared to what we had before this. Also, will C# be coming out with the same type of compiler?
I'm confused on the results of this code. The results extracts the tag "div" but why isn't the results containing the word "Yoga"? Shouldn't the result have only one element because it should exit the for loop after finding the first element? The results show hundreds of elements
Dim ElementCollection2 As HtmlElementCollection = WebBrowser1.Document.GetElementsByTagName("div")
For Each curElement As HtmlElement In ElementCollection2
[code].....
I wanted to know what the main areas are and what the array is actually doing in the code. I know that dim is declaring the variables, but how do i exactly explain this code line by line.
PS: the areas in red are the main areas im trying to understand annotate.
Public Class Form1
Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
End Sub
[code]....
If i have a class called A and a class called B, if B inherits A that means A is the super class and B is the subclass. I have been asked to describe why class A is not an abstract class but as i see it class A is an abstract class A, as it has been created for Class B to use in the future, is it something to do with Class B not being able to access the fields in Class A as although they are private by default?
[Code]...
As far as I understand from the docs, it seems that Application.Run() starts a message loop on the current thread, which in turns enables it to process user input (Is that right?).The overloaded version Application.Run(Form) basically does the same, only it exists when the form closes, and it shows the form by default.timer ticks after 20mns, and has to execute say approx. 15 tasks one by one, every time creating an instance of a progress dialog, initially hidden in the taskbar.
View 1 RepliesLooking at the following code snippet in VS2008 (this is from the SBS book)
Dim HumanAge As Integer = 0
If HumanAge <> 0 And 7 / HumanAge <= 1 Then
MsgBox("1 dog year or older")[code]....
I expect to get a runtime error, because And evaluates both conditions, which is why in this case AndAlso should be the better operator to use. When I try this code there is no difference in behavior between 'And' & 'AndAlso'. In neither case I get a
runtime error, not even when I flip the conditions around. Is this by design, a lucky accident, or do I just not get it?
I have a situation in a program I'm writing where I'm not sure of the best way of coding a couple of objects and was hoping for a few pointers.I am using VB.NET 2003, so F/wrk v1.1. My business is horticultural in nature and I'm trying to help streamline the business with a new order fulfillment app.In my program, I have products. Some products don't have any component parts, but others are made up of a selection of plants.For example: we sell a trowel, which obviously doesn't have any component parts. But we also sell a large vegetable garden, which is made up of, say, 20 rocket plants, 30 salad plants, 5 spring onions, etc.[code]I believe the ProductContents table is technically referred to as a 'join table'?
I have written the classes in VB.NET which load, save, edit the Products and the Plants. I also have Manager classes which store collections of these objects (ProductMgr, PlantMgr).I have dealt with situations before with join tables where there are only two columns which are both FKs and both make up a composite PK (ie - to express a one-to-many relationship). This is pretty straightforward (using my product/plant tables as an example) because when I load an individual Product from the database, I also run a second SELECT query which returns any PlantIDs associated with that PlantID from ProductContents. I store that in an array of integers within the Product object. I can then load Plants from the PlantMgr object based on the PlantIDs stored in this array. I kind-of do the reverse when I save the Product to the database, I run a second INSERT query which updates the ProductContents table with the Plants associated with the Product.Where I'm getting stuck is with the inclusion of the extra 'Quantity' column. I can no longer store the PlantIDs in an array of Integers because I also need to store the Quantity associated with that Plant. I also can't use the PlantMgr object any more (to express which Plants are in each Product) because it also doesn't include any information about Quantity.I was just wondering if there is a standard way of handling this kind of situation, where I have a 'join table' which also includes extra columns as well as the two columns that identify the join.
